From earliest times to the present day, salt (sodium chloride) has been popularly regarded as a health giving, necessary and satisfying addition to the human diet. Some advocates of salt explain that man's affinity for this mineral is an inevitable by product of his evolutionary origins in the primordial oceans. It is a fact that the sea is our biological mother, and that every species which has evolved out of the sea has kept one important marine characteristic- an unvarying and unique percentage concentration of salt in its bodily fluids. In order to ensure the exact degree of sodium chloride concentration which is required, land animals have developed elaborate physiological systems of chemical regulation and ionic balance.
These mechanisms function to maintain and recycle sodium and chloride ions in the body, since salt is no longer an accessible part of our ecological environment, as it was in the oceans. Paradoxically, sodium chloride is at the same time one of the most abundant and rarest of chemicals on the planet. There are billions of tons in the ocean (each litre of sea water contains 32-35 gm.) but for plants and animals on dry land, it is practically unobtainable in its mineral form. So, for the last millions of years, all forms of land based life on earth have had to evolve without it. This holds true for humans as well, of course; had salt been an indispensable food item, we would not be here now to discuss it.
The human being is the only land animal who has gained an unlimited access to salt in its crystalline form and who uses it regularly. It is true that many vegetarian animals, such as deer, love salt when they can get it, but they usually do not find it on their own, and they certainly don't need it. However, their blood contains the physiologically correct quantity of salt, and their health is as good as ours. Where does their salt come from? The answer is that meat and vegetables contain sufficient quantities of salt to support all animal life, including human, without the need for additional supplies.
There is no denying that salt is a staple ingredient in the fluids of human life. The body contains about 200 gm. of sodium chloride in varying percentages in all the tissues and fluids of the body, including the blood, lymphatic, cerebrospinal, and intra- and extra-cellular fluids. With potassium, it is the major regulator of fluid exchanges and many important chemical reactions. From the digestive point of view, sodium chloride is a necessary component of hydrochloric acid, the powerful digestive juice secreted by the stomach. It also has an anti-toxic and antibacterial action, decreasing the effects of poisons circulating in the body and helping to eliminate them.
However, just because a little salt is such a good thing, it does not follow that more salt is even better. It is commonly believed that excessive salt intake provides a margin of safety against salt depletion, and that any extra salt can be easily eliminated in the urine, perspiration and faeces. This is not the case at all. Well functioning kidneys, working at their maximum capacity, only evacuate 5 gm. of salt a day, while the average European salt intake is 10-15 gm. per day, and in Japan it is as high as 20 gm.
During evolution, when primitive man did not have access to salt in its mineral form, the kidneys were conceived by nature to conserve salt and not to eliminate it. In fact, much of the work of the kidneys is directed towards re-filtering salt from the urine back into the bloodstream for recycling. Even the hydrochloric acid is neutralized by glands in the duodenum after the food leaves the stomach, and is transformed back into sodium chloride and water.
Salt deficiency thus generally results from excessive loss of salt from the body rather than inadequate intake. This is most commonly caused by a very high degree of sweating due to extreme physical exertion or very hot, tropical climates. It can also be caused by renal failure or by a sudden loss of salt-containing fluids due to vomiting or injury. However, in reasonably temperate climates, normal sedentary people lose negligible amounts of salt through these means. Besides, just because salt is being expelled from the body, this does not mean that we must necessarily try to immediately replace it, any more than we should try to replace lost alcohol or any other toxin or poison that the body is eliminating.
Because the eliminative capacity of the kidneys is generally exceeded, one may well wonder where the extra salt goes. As the percentage of sodium chloride in the blood always remains constant, the body must find other ways of re-establishing the salt/water balance. The first way is through dilution, by increased intake of non-saline fluids. This is why we become thirsty after eating salty foods, not because of body dehydration. To dilute 4 gm. of salt, half a litre of water has to be drunk. When we drink in order to dilute salt, the extra fluid is not readily eliminated by the kidneys, and so the volume of blood increases. This raises the blood pressure and forces the kidneys to work harder to filter a larger quantity of blood.
When dilution is no longer sufficient, the salt is stored. It goes into bones, tendons, ligaments and connective tissues al! throughout the body, which rapidly become clogged with salt. It is also stored under the skin, and it is this subcutaneous salt which is expelled during profuse perspiration. The tissues chosen for salt storage have the ability to decompose sodium chloride, as they absorb chloride and reject sodium. Chloride accumulates in the body for years together without any apparent perturbation, up to the time that the ultimate storage limit has been reached. Then salt becomes verily a poison.
There are many factors which contribute to high blood pressure: the nature and lifestyle of the individual, high levels of stress, smoking and unhealthy eating habits. But the major factor is very simple: too much salt in the food. Studies have shown that the tendency of increasing blood pressure with increasing age does not occur in populations which do not take much salt in their daily diet, and eat a lot of vegetables rich in potassium, which naturally balances salt. For example, consumption of salt in New Guinea is less than 0.5 gm. a day, and blood pressure among 70 year olds is the same as it is for people in their 20's.
On the other hand, statistics reveal a direct relationship between salt consumption and cardiovascular disease in countries where salt consumption is very high. In Korea, for example, medical conditions attributable to hypertension are widespread. Hospital wards are full of people in comatose states, paralyzed by cerebral apoplexy, and many pregnancies are complicated by eclampsia due to high blood pressure. In Japan, salt intake has also been linked to the high incidence of stomach cancer.
In modern populations, the frequency of high blood pressure increases with age. It occurs in 70% of all people over 60. Even in the population under 30, about 30% have related vascular problems. High blood pressure is not as usual in young women as it is in young men, but as age advances it becomes more frequent. The estimated additional life expectancy of a 35 year old with even slightly elevated blood pressure is the same as that of a person 20 years older with normal blood pressure; it is 24 years in both cases. In developed countries, cardiovascular impairment is responsible for almost half of the deaths, and high blood pressure is first among the factors which contribute to it.
Forty years ago, when no medicine was available to relieve high blood pressure, doctors found that by reducing sodium in the diet, arterial pressure was very effectively lowered. This is still the first line of treatment in all high blood pressure therapy, and is much cheaper and less hazardous than taking drugs.
High salt consumption also acts upon the mucus membranes of the breathing tracts. Among the symptoms are: repeated sneezing, frequent colds and loss of the related senses of taste and smell. When over consumption continues for an extended period, these characteristics increase and emerge as chronic coryza, swelling of the nasal mucus membranes, catarrh of the breathing tracts, nervous coughs and exacerbation of asthma.
Negative effects on the digestive system include acidity, swelling of the salivary glands, chronic irritation of the palatal mucosa and throat, and swelling of the tonsils. Abnormally high thirst provokes an excessive intake of fluids which disturbs the digestion by diluting the digestive juices. This may induce constipation or diarrhoea, and abnormal modifications of the linings of the large intestines and anus, causing piles.
When the kidneys are forced to filter ten times as much salt as they are designed to, the probability of kidney impairments is bound to increase. Excessive salt can also cause sexual disturbances, such as premature ejaculation in males. In females it can be responsible for pruritis of the genitals and decreased secretion of vaginal lubrication. Doctors have also found that discontinuance of salt leads to improvement of rheumatism and arthritis, and some types of ocular diseases and migraines.
We overuse salt from childhood, and serious conditions derived from an excess of sodium may be found very early. One important source of extra sodium is dehydrated cow's milk, which contains three times as much salt as human milk. The water in which it is dissolved is often salted as well. Commercial baby foods are also highly salted to make them palatable to mothers as well as babies. Once the insidious habit of eating salt is acquired in infancy and childhood, it is very difficult to change.
Food prepared commercially, even bread, always contains too much salt. So begin to look around you, and look at your own eating habits. Are you sure you are not overusing salt when you prepare your food, and then pouring it on again at the table, only to gratify your salt habit? An excess of salt in our daily life pollutes our alimentation just as exhaust fumes, sewage and industrial wastes pollute our environment.
It is said that in some monasteries, it has been possible to suppress harmful and stimulating products such as meat, fermented drinks, coffee and tea, but never has it been possible at the same time to suppress salt. The idea of reducing salt seems impossible at first. In fact, it takes only a few days before the food becomes as tasty and appetizing as before. Over-salting food is a habit, and it can definitely be broken. We can easily live with less salt, just as we can live with less sugar. The most important requirement is to have the agreement of the cook.
In 1930, in his book 'A Guide to Health', Mahatma Gandhi wrote, 'Vegetarian food contains in itself enough salt, so it is unnecessary to add any other quantity. Nature has foreseen the necessary quantity of salt to keep in good health.' Gandhi states also that persons who do not add salt to their food have purer and healthier blood, which makes them more resistant to infection and disease.
'I have never been able to find any objection to stopping the use of salt, just the opposite,' says Gandhi. But he never managed to convince his wife, who used to love salt very much. 'I am convinced', he says, 'that had she been able to give up salt, she could have been cured of her sickness and would still be alive.'